The Syrian president said in remarks published Friday that he is adamant his regime will not fall and he also lashed out at Gulf countries, which he accused of using their enormous oil wealth to try to drive him from power.

Bashar Assad's comments came as an opposition group, the National Coordination Body for Democratic Change in Syria, accused the regime of being behind the disappearance of two of its leaders.

Abdul-Aziz al-Kheir and Ayas Ayyash were expected to take part in a conference Sunday in Damascus by some 20 Syrian groups that are calling for Assad to step down. But they disappeared Thursday along with a friend who had picked them up at Damascus International Airport, the group said.

The group's head, Hassan Abdul-Azim, told The Associated Press by telephone that the regime was believed to be behind the disappearance.

Syria's crisis began in March last year with anti-government demonstrations inspired by the Arab Spring and demanding reforms. The protests were met with a brutal crackdown by the regime. Syria later became embroiled in a civil war between forces fighting for Assad and those trying to topple him.

Activists now say that nearly 30,000 people have been killed since the crisis began, the vast majority of them civilians.

After Assad's remarks were published, Syrian Information Minister Omran al-Zoebi told state-run TV on Friday that the president had received nine Egyptian journalists and had a chat with them about the latest developments in the country.